Fabric softening products are known in the art to provide effective softness to the treated fabrics. However, a problem encountered upon storage at low temperature, i.e. at sub 0.degree. C. temperature, is the freezing of the product which, when placed at higher temperatures results in a product which does not recover to a uniform dispersion with acceptable flow characteristics.
Accordingly, it is an object of the invention to provide a fabric softening product which has effective freeze-thaw recovery.
One solution to fulfill such need is described in GB-1,098,793 with the use of sulphate salts of fatty amines in fabric softening compositions.
Still another solution is described in EP-A-0,507,478 which provides the mixing and melting of the cationic fabric softener with a nonionic stabilising agent before dispersing it in water. However, a problem encountered with such a process is that processing equipment such as high shear mixers are needed so that the resulting cost of the formulation is increased.
Accordingly, it is also an object of the invention to provide a fabric softening product which only necessitates minimal processing equipment.
It has been observed that without high shear during the processing of a fabric softening product, the formation of dye speckles arises, whilst with high shear the formation of undispersed dye particles in the fabric softening product is avoided.
Accordingly, the formulator of a softening composition is faced with the dual challenge of formulating a softening composition which has good dye homogeneity, without the need for a high shear mixing equipment.
The Applicant has now found that the addition of the dye component together with a nonionic alkoxylated surfactant to the finished cold softening product fulfills such needs.
Indeed, application of the dye and nonionic alkoxylated surfactant to the cold finished product is made by simple mixing. The composition obtained results in an homogenous dispersion.
An advantage of the invention is that for resulting fabric softening products in diluted form made by the invention process, less mechanical shear is required compared to products made by mixing the fabric softener and nonionic before dispersion in water. Not to be bound by theory, it is believed that the nonionic surfactant micellizes the dye and subsequently forms mixed vesicles with the softener active. In this manner the dye is efficiently dispersed and the product acquires good freeze thaw recovery.